#ifndef XRPL_NODESTORE_BASE_H_INCLUDED
#define XRPL_NODESTORE_BASE_H_INCLUDED

#include <xrpl/basics/StringUtilities.h>
#include <xrpl/basics/random.h>
#include <xrpl/beast/unit_test.h>
#include <xrpl/beast/utility/rngfill.h>
#include <xrpl/beast/xor_shift_engine.h>
#include <xrpl/nodestore/Backend.h>
#include <xrpl/nodestore/Database.h>
#include <xrpl/nodestore/Types.h>

#include <boost/algorithm/string.hpp>

#include <iomanip>

namespace ripple {
namespace NodeStore {

/** Binary function that satisfies the strict-weak-ordering requirement.

    This compares the hashes of both objects and returns true if
    the first hash is considered to go before the second.

    @see std::sort
*/
struct LessThan
{
    bool
    operator()(
        std::shared_ptr<NodeObject> const& lhs,
        std::shared_ptr<NodeObject> const& rhs) const noexcept
    {
        return lhs->getHash() < rhs->getHash();
    }
};

/** Returns `true` if objects are identical. */
inline bool
isSame(
    std::shared_ptr<NodeObject> const& lhs,
    std::shared_ptr<NodeObject> const& rhs)
{
    return (lhs->getType() == rhs->getType()) &&
        (lhs->getHash() == rhs->getHash()) &&
        (lhs->getData() == rhs->getData());
}

// Some common code for the unit tests
//
class TestBase : public beast::unit_test::suite
{
public:
    // Tunable parameters
    //
    static std::size_t const minPayloadBytes = 1;
    static std::size_t const maxPayloadBytes = 2000;
    static int const numObjectsToTest = 2000;

public:
    // Create a predictable batch of objects
    static Batch
    createPredictableBatch(int numObjects, std::uint64_t seed)
    {
        Batch batch;
        batch.reserve(numObjects);

        beast::xor_shift_engine rng(seed);

        for (int i = 0; i < numObjects; ++i)
        {
            NodeObjectType const type = [&] {
                switch (rand_int(rng, 3))
                {
                    case 0:
                        return hotLEDGER;
                    case 1:
                        return hotACCOUNT_NODE;
                    case 2:
                        return hotTRANSACTION_NODE;
                    case 3:
                        return hotUNKNOWN;
                }
                // will never happen, but make static analysis tool happy.
                return hotUNKNOWN;
            }();

            uint256 hash;
            beast::rngfill(hash.begin(), hash.size(), rng);

            Blob blob(rand_int(rng, minPayloadBytes, maxPayloadBytes));
            beast::rngfill(blob.data(), blob.size(), rng);

            batch.push_back(
                NodeObject::createObject(type, std::move(blob), hash));
        }

        return batch;
    }

    // Compare two batches for equality
    static bool
    areBatchesEqual(Batch const& lhs, Batch const& rhs)
    {
        bool result = true;

        if (lhs.size() == rhs.size())
        {
            for (int i = 0; i < lhs.size(); ++i)
            {
                if (!isSame(lhs[i], rhs[i]))
                {
                    result = false;
                    break;
                }
            }
        }
        else
        {
            result = false;
        }

        return result;
    }

    // Store a batch in a backend
    void
    storeBatch(Backend& backend, Batch const& batch)
    {
        for (int i = 0; i < batch.size(); ++i)
        {
            backend.store(batch[i]);
        }
    }

    // Get a copy of a batch in a backend
    void
    fetchCopyOfBatch(Backend& backend, Batch* pCopy, Batch const& batch)
    {
        pCopy->clear();
        pCopy->reserve(batch.size());

        for (int i = 0; i < batch.size(); ++i)
        {
            std::shared_ptr<NodeObject> object;

            Status const status =
                backend.fetch(batch[i]->getHash().cbegin(), &object);

            BEAST_EXPECT(status == ok);

            if (status == ok)
            {
                BEAST_EXPECT(object != nullptr);

                pCopy->push_back(object);
            }
        }
    }

    void
    fetchMissing(Backend& backend, Batch const& batch)
    {
        for (int i = 0; i < batch.size(); ++i)
        {
            std::shared_ptr<NodeObject> object;

            Status const status =
                backend.fetch(batch[i]->getHash().cbegin(), &object);

            BEAST_EXPECT(status == notFound);
        }
    }

    // Store all objects in a batch
    static void
    storeBatch(Database& db, Batch const& batch)
    {
        for (int i = 0; i < batch.size(); ++i)
        {
            std::shared_ptr<NodeObject> const object(batch[i]);

            Blob data(object->getData());

            db.store(
                object->getType(),
                std::move(data),
                object->getHash(),
                db.earliestLedgerSeq());
        }
    }

    // Fetch all the hashes in one batch, into another batch.
    static void
    fetchCopyOfBatch(Database& db, Batch* pCopy, Batch const& batch)
    {
        pCopy->clear();
        pCopy->reserve(batch.size());

        for (int i = 0; i < batch.size(); ++i)
        {
            std::shared_ptr<NodeObject> object =
                db.fetchNodeObject(batch[i]->getHash(), 0);

            if (object != nullptr)
                pCopy->push_back(object);
        }
    }
};

}  // namespace NodeStore
}  // namespace ripple

#endif
